Disengageable spring clutch



June 18, 1929; w. c. STARKEY 1,718,197

DISENGAGEBLE SPRING CLUTCH Filed May 16, 1925 IIL l l l n IN VEN TOR. 2%//7/7z fra/v .5MP/rf);

i4 TToRNEY.

vvPatented June 18, 1929.

NirED STATES 1,718,197 PATENT OFFICE.

WILLIAM/ CARLETON STARKEY, OF INDIANAPOLIS, INDIANA, ASSIGNOR TO L. G.S.

DEVICES CORPORATION. 0F INDIANAPOLIS, INDIANA, A CORPORATION OF IN-DIANA.

DISENGAGEABLE SPRING CLUTCH.

Application filed May 16, 1925. Serial No. 30,763.

It is the object of my invention to produce a clutch which may operatebetween two relatively rotatable, coaxial membersvand which ffmay lbeengaged to clutch said two members together when they tend to rotaterelatively in onefdirection while permitting free relative rotation inthe other direction, the clutch when disengaged permitting free relativerotation of the rotating members in either direction.

I accomplish the above object by providing the two relatively rotatablemembers with alined circular recesses, and I provide a helical springextendingbetween said two members and received -within both recesses,this spring in its unstressed condition being slightly smaller inexternal diameter than the diameter of such recesses; and I providemeans for engaging this spring with one of the rotatable members so thatthe spring may unwind and expand against the walls of said recesses toclutch the two members together-when they tend to rotate relatively in adirection to unwind the spring.

'Ihe accompanying drawing illustrates several modifications of myinvention; Fig. 1 is a longitudinal section of my clutch in engagedposition' and arranged to operate between a shaft and a gear mountedthereon; Fig. 2 is a longitudinal sectional View of the clutch shownin'Fig. 1, but with the clutch disengaged; Fig. 3 is a longitudinalsection of a clutch arranged to connect two shafts, the clutch beingshown as in engaged position; Fig. 4 is a longitudinal section of theclutch shown in Fig. 3, but with the spring disengaged; Fig. 5 is alongitudinal section of a clutch-similar in purpose to Fig. 1, buteinbodyinga different method of engaging the clutch; Fig. 6 isa'longitudinal section of the clutch shown in Fig. 5, with the springdisengaged; and Fig.'7 is a transverse section on the line 7 7 of Fig.1'..

In the modification of my invention illustrated in Fig. l, the clutch isarranged to connect a gear 10 to a shaft 11. A collar 12 is rigidlymounted on the shaft 11, as by the taper pin 13, and is provided on itsopposite end with a central cylindrical recess for the reception of vahelical spring 14. The spring 14 extends beyond the end of the co1lar`12and into a cylindrical recess in the hub 15 of the gear 10. The recessin the hub 15 is shoul v dered as at16 to permit the reception of thecollar 12 within such recess, the end of the collar 12 abutting againstthe shoulder 16.

hub 15 and is provided with splines 21 which mate with corresponding.splines in the gear hub. The inner end of this sleeve 20 is providedWith a recess for the reception of the inturned end 14l of the coiledspring 14. The sleeve 2O may also be provided exteriorly of the gear hubwith anannular groove 22, to be used in connecting the sleeve 20 to anyconvenient well known shifting mechanism for shifting vsuch sleeveaxially of the shaft 11.

IZVhen the spring 14 is free from any stresses, as it is with the partsin the position shown in Fig. 2, its external diameter is slightlysmaller than the internal diameter of the recesses in the collar 12 andgear hub 15, so that with the clutch disengaged as in Fig, 2, the springdoes not bear against the walls of these recesses. 'Io engage theclu'tch,

the ,sleeve 2() is moved axially of the shaft from the position shown inFig. 2 to the position shown in Fig. 1, whereupon .the squared end ofthe spring 14 engages a shoulder v12 on the collar 12. lIf the shaft 11and the gear 10 are rotated relatively to each other be reduced indiameter and to become disengaged from the walls of the recesses, thuspermitting free relative rotationof the gear. and the shaft 11. y

In the construction illustrated in Figs. 3 and 4, the clutch is adaptedto form a driving connection in one direction between twov coaxialvshafts 11 and 25. The shaft 11 carries a collar 12 keyed to the shaftby the taper pin 13, these parts being the same as the correspondingp'arts shown in Figs. 1 and 2- The shaft 25 carries the sliding sleeve20 which has they lsplines2l Qd the groove 22 as Should the gear 10 andshaft i .11 tend to rotate in the direction to wind the spring 14, suchwinding causes the spring to also shown in' Figs. 1 and 2. In this modi'cation,-however, the sleeve 20 is l eyed to the shaft by means of a key26 which prevents relative rotation of the sleeve 20 and the shaft 25while permitting the sleeve 20 to slide on such shaft.

1 and 2', is prdvided with a shouldered recess y fo'r the reception ofthe spring 28 such recess being the samevas that in the gear hub15 shownin Fig. 1. The spring 28 has an inturned end 28 which is received Withina recess in the sliding sleeve 20, exactly as the in-turned end 14 ofthe spring 14 shown in Figs. 1 and 2 is received in the recess in thesleeve 20.

'Ihe spring 28 of the modification shown in Figs. 3 and 4 differs fromthe spring 14 shown in Figs. 1 and 2. The spring 28 is an openf woundspring, so that when it is u nstressedk its turns are separated from oneanother as shown in Fig. 4. After wlnding, the sprlng vis compresseduntil the coils are together and the exterior surface of the spring isthen finished, as bygrinding, to an extdrnal di# ameter slightly largerthan the internal diameter of the recesses in the collar 12 and themember 27. When the coiled spring so finished is permitted to take itsnormal' posi-4 tion with the spring-turns separated, its diameter willbe reduced so that when the spring 28 is placed in position as shown inFig. 4,

its external diameterV is slightly? lessl than the internal diameter ofthe recesses in the 1 parts 12 and 27. As a result, when the sleeve 20is in its right hand position as shown in Fig. 4, the spring 28 is outofengagement with the walls of the recesses. When the sleeve 20 is movedto the left to the position shown in Fig. 3,'the. axial compression ofthe spring results in an increase in its external diameter and causesthe spring to bear against the ywalls of the recesses. If, while inthis' position, the shafts 11 and 25 tend to rotate in the direction tounwind this spring,

the spring expands and firmly grips'the surv faces of the recesses, thuslockingthe two shafts together. Should the two shafts tend to rotaterelatively ina direction to wind the spring, the spring decreases indiameter and permits relative' rotation of the two shaf The de'viceillustrated in Figs. 5 and 6 has the same function as that illustratedin Figs. 1, 2, and 7 and contains the same lparts 'numbered 10 to 22 asdoes the device of Figs.

l yso 1, 2, an'd 7 However, in place of providing the shoulder 12 inthebottom of the recess in the collar 12, this recess, near the bottom istapered to a diameter, smaller than the eX- ternal diameter of thespring14 when such spring is not subjected'to any stress. WithV lthe4sleeve 20 in theposition shown in Fig.

6, thespring 14 is moved-out-of this tapered position of the recess inthe collar-12, and

A member 27, corresponding in function to the gear .hub 15 shown 1nFigs.

thus is free from engagement with the walls of either recess. When thesleeve 20 is moved to the position shown in Fig. 5, the left hand end ofthe spring 14 engages the tapering walls of the recess of the collar 12.If, with the spring 14 and sleeve 20 in .the posltlon' shown in Fig. 5,the gear 10 and'theshaft 11 tend to rotaterelatively in a direction tounwind the spring 14, the spring is expanded.

and grips the walls of the recesses in the collar 12 and the gear-hub15. Free relative rotation in the other direction is permitted, as suchrotation permits the spring to be reducedl in diameter and to be freefrom the walls of these recesses. l

Each of the modifications illustrated and described makes it possible toconnect ,two relatively "rotating parts so that they will be lockedtogether when relative rotation in one direction tends to occur and willbe free to l disengaged from on of said members so that 1t w1ll lnotgrip the walls of its associated recesses upon relative rotation of saidrotatable members 1n either direction, and means for engaging saidspring with that one of said members from which it is normally'disengaged so that upon relative rotation of said twol members in thedirection tending to unwind said spring said spring will expand to gripirmly the walls ofits associated recesses. f l

2. In combination, two relatively rotatable members, said members beingprovided with alined`circular recesses, a coil-spring located in saidrecesses, said coil-spring being normally operatively disengaged fromone of said members so'that. it will not grip the walls of bothassociated recesses upon relative rotation of said rotatable members ineither direction, and means for engaging said spring -with that one ofsaid members from which it is normally disengaged so that upon relativerotation of said two members in the direction tending to unwind saidspring said of its associated recesses.

3. In combination, tworelatively rotatable members, said members beingprovided with alin'ed circular recesses, a coil-spring located llOYspring will expand to grip firmly the walls in said recesses, saidcoil-spring being rotatable with one of said members, and means foroperatively engaging and disengaging said spring with the other of said`members, said spring when disengaged from said last named memberpermitting free relative rotation. of said rotatable members in eitherdirection.L f

4. In combination, two relatively rotatable members having alinedcircular recesses,- a

coil spring coaxial with said members and located in said recesses, oneof said recesses havinga diameter greater than the externaldiamconnection with one o eter of said spring when said'spring isunstressed, and means for applyin a torque to said springto cause it toexpan into gripping engagement with the walls of the recesses in both ofsaid members to clutch them together.

5. In combination, two relatively rotatable members, a coil-springrotatable with one of said members and normally free from connectionwith the other member whereby said two members' are normally free torotate relatively in either direction, said members having surby saidtwo members may normally rotatel relatively in either direction, saidmembers having surfaces arranged to be gripped by said coil-spring upona change in its diameter, and releasable means operative to cause saidspring to transmit a torque between said two members whereby thediameter of said sprin will be changed and said spring will grip sucsurfaces.

7. In combination, two relatively rotatable members, said 'members beingprovided with alined circular recesses, a coil spring located in saidrecesses and being rotatable with one of said members, an abutmentrotatable with the other of said members, and means for causingengagement and disengagement of said abutment with the adjacent end ofsaid coil springt 8. The `combination set forth in claim 6 with theaddition that said surfaces are arranged to be gripped by saidspringwhen the torque which it transmits is 1n one direction and to be freedfrom said spring when the torque is in Vthe other direction.

In witness whereof, I have hereunto set my hand at Indianapolis,Indiana, this 14th day of May, A. D. one thousand nine hundred andtwenty-five.

WILLIAM* CARLETON STARKEY.

